Isothermal heating apparatus

ABSTRACT

An isothermal heating apparatus includes a plate including formed therein a heat pipe circuit in which working fluid is charged, and a heating mechanism heating the working fluid. The heat pipe circuit includes a header portion at which the working fluid is heated and evaporated and a plurality of branch portions in which vapor produced by vaporization of the working fluid exchanges heat with the plate and condensates, the branch portions branching off from the header portion. The heating mechanism is provided on an evaporating surface side of the header portion with which the working fluid is in contact when the heating mechanism heats the working fluid. The isothermal heating apparatus can achieve isothermal heating of a heat-treatment subject and size reduction of the apparatus.

TECHNICAL FIELD

The present invention relates to an isothermal heating apparatus thatheats a heat-treatment subject into an isothermally heated state.

BACKGROUND ART

A conventional technique regarding an isothermal heating plate thatheat-treats a heat-treatment subject into an isothermally heated stateis disclosed in, for example, Japanese Laid-Open Patent Publication No.9-314561 (PTL 1) or Japanese Laid-Open Patent Publication No.2007-294688 (PTL 2).

FIG. 20 is a perspective view showing a structure of an example of aconventional isothermal heating plate. An isothermal heating plate shownin FIG. 20 has a structure in which the both ends of each of a pluralityof through holes 102 a formed in a plate 101 are closed with lids 107 aand 107 b to form a sealed container 107, the inside of this sealedcontainer 107 is evacuated and then a predetermined amount of workingfluid is charged, and a heater 106 is brought into thermal contact withthe bottom of plate 101 with a heat transfer block 104 interposedtherebetween.

FIG. 21 is a plan view showing a structure of another example of aconventional isothermal heating plate. FIG. 22 is a side view showingthe structure of the other example of the conventional isothermalheating plate. The isothermal heating plate shown in FIGS. 21 and 22 hasa pipe 123 arranged in a plurality of holes formed in a plate 121 toform a meandering circuit of a pipe container, and has an evaporator 143with an entrance 141 serving as one end of the meandering circuit beingconnected to the upper part and an exit 142 serving as the other end ofthe circuit being connected to the lower part to form a singlecommunication circuit with the meandering circuit. The inside of thissingle communication circuit is evacuated and then a predeterminedamount of working fluid 131 is charged, and working fluid 131 is heatedby a heater 126 fitted in evaporator 143.

CITATION LIST Patent Literature

-   PTL 1: Japanese Laid-Open Patent Publication No. 9-314561-   PTL 2: Japanese Laid-Open Patent Publication No. 2007-294688

SUMMARY OF INVENTION Technical Problem

As described above, various techniques for the isothermal heatingapparatus that isothermally heats a heat-treatment subject have beenproposed so far. However, the isothermal heating apparatus is requestedto have the capability of heating a subject much more isothermally, andin addition, size reduction of the apparatus is also required. Theconventional apparatus disclosed in each piece of literature mentionedabove do not necessarily satisfy these points, but there is still roomfor improvement.

The present invention was made in view of the above-described problems,and has a main object to provide an isothermal heating apparatus capableof isothermally heating a heat-treatment subject and achieving sizereduction of the apparatus.

Solution to Problem

An isothermal heating apparatus according to the present inventionincludes a plate having formed therein a heat pipe circuit in which aworking fluid is charged, and heating means heating the working fluid.The heat pipe circuit includes a header portion at which the workingfluid is heated and evaporated and a plurality of branch portions inwhich vapor produced by vaporization of the working fluid exchanges heatwith the plate and condensates, the branch portions branching off fromthe header portion. The heating means is provided on a wall surface sideof the header portion with which the working fluid is in contact whenthe heating means heats the working fluid.

In the above-described isothermal heating apparatus, preferably, theplate is formed to have a rectangular shape in plan view, the headerportion extends along one side surface of the plate, and the branchportions are provided to extend toward an other side surface of theplate opposed to the one side surface.

In the above-described isothermal heating apparatus, preferably, theplurality of branch portions are arranged in parallel to one another.Still preferably, the heat pipe circuit further includes a couplingportion coupling the branch portions. The coupling portion may coupletips of the branch portions extending from the header portion. Aplurality of the coupling portions may be provided and may be arrangedin parallel to one another.

In the above-described isothermal heating apparatus, preferably, theheating means includes a heater, a heat transfer block formed with arecess and storing the heater in the recess, and a heater holding plateholding the heater in the recess.

In the above-described isothermal heating apparatus, preferably, theheating means includes a fixing member fixing the heater holding plateand the heat transfer block integrally to the plate.

The above-described isothermal heating apparatus may include a thermallyconductive interposed member interposed between the plate and the heattransfer block. The heating means may include a thermally conductiveinterposed member interposed between the heat transfer block and theheater holding plate. The heating means may include a thermallyinsulative interposed member interposed between the heat transfer blockand the heater holding plate.

In the above-described isothermal heating apparatus, preferably, ahollowed portion storing the heater is formed in the heater holdingplate at a position opposed to the recess.

In the above-described isothermal heating apparatus, preferably, a highperformance boiling surface promoting boiling of the working fluid isformed in the wall surface with which the working fluid is in contactwhere the working fluid is heated.

In the above-described isothermal heating apparatus, preferably, a widthby which the heating means is in thermal contact with the plate is lessthan or equal to a width of the wall surface with which the workingfluid is in contact where the working fluid is heated.

Advantageous Effects of Invention

According to the isothermal heating apparatus of the present invention,a heat-treatment subject can be heated isothermally, and size reductionof the apparatus can be achieved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view of an isothermal heating apparatus of a firstembodiment of the present invention.

FIG. 2 is a sectional view of the isothermal heating apparatus takenalong the line II-II shown in FIG. 1.

FIG. 3 is a sectional view of the isothermal heating apparatus takenalong the line shown in FIG. 1.

FIG. 4 is a sectional view showing details of the structure of heatingmeans.

FIG. 5 is a sectional view showing a first variation of the isothermalheating apparatus of the first embodiment.

FIG. 6 is a sectional view showing a second variation of the isothermalheating apparatus of the first embodiment.

FIG. 7 is a sectional view showing a third variation of the isothermalheating apparatus of the first embodiment.

FIG. 8 is a sectional view of an isothermal heating apparatus of asecond embodiment.

FIG. 9 is a sectional view of an isothermal heating apparatus of a thirdembodiment.

FIG. 10 is a sectional view of a variation of the isothermal heatingapparatus of the third embodiment.

FIG. 11 is a sectional view of an isothermal heating apparatus of afourth embodiment.

FIG. 12 is a sectional view of an isothermal heating apparatus of afifth embodiment.

FIG. 13 is a sectional view of an isothermal heating apparatus of asixth embodiment.

FIG. 14 is a sectional view showing another example of arrangement of aplate.

FIG. 15 is a sectional view showing another example of arrangement of aplate.

FIG. 16 is a plan view of an isothermal heating apparatus of a seventhembodiment.

FIG. 17 is a plan view of another example of the isothermal heatingapparatus of the seventh embodiment.

FIG. 18 is a plan view of another example of the isothermal heatingapparatus of the seventh embodiment.

FIG. 19 is a plan view of another example of the isothermal heatingapparatus of the seventh embodiment.

FIG. 20 is a perspective view showing the structure of an example of aconventional isothermal heating plate.

FIG. 21 is a plan view showing the structure of another example of theconventional isothermal heating plate.

FIG. 22 is a side view showing the structure of the other example of theconventional isothermal heating plate.

DESCRIPTION OF EMBODIMENTS

Hereinbelow, embodiments of the present invention will be describedbased on the drawings. It is noted that, in the drawings, the same orcorresponding portion has the same reference number allotted, anddescription thereof will not be repeated.

First Embodiment

FIG. 1 is a plan view of an isothermal heating apparatus of a firstembodiment of the present invention. FIG. 2 is a sectional view of theisothermal heating apparatus taken along the line II-II shown in FIG. 1.As shown in FIGS. 1 and 2, the isothermal heating apparatus of the firstembodiment includes a plate 1 having a rectangular plate shape. Plate 1is made of a material having high thermal conductivity represented by,for example, copper, aluminum or the like. The material making up ofplate 1 can be arbitrarily selected depending on isothermal propertyrequired of a heat-treatment subject.

Plate 1 is formed to have a rectangular shape in plan view. A frontsurface 1 a which is one surface of plate 1 is formed flat such that aheat-treatment subject, such as an organic material for semiconductormanufacture, for example, can be mounted and heated thereon. Heatingmeans 3 is attached to a rear surface 1 b which is the other surface ofplate 1.

As shown in FIG. 1, a heat pipe circuit 2 is formed in plate 1. Heatpipe circuit 2 includes a header portion 2 b and a plurality of branchportions 2 a branching off from header portion 2 b. Header portion 2 bis arranged to extend along a side surface 1 c constituting one sidesurface of plate 1 when plate 1 formed to have a rectangular shape inplan view is planarly viewed. Branch portions 2 a are provided to extendfrom header portion 2 b toward a side surface 1 d constituting the otherside surface of plate 1 opposed to side surface 1 c. Plurality of branchportions 2 a are arranged in parallel to one another, as shown inFIG. 1. Each of plurality of branch portions 2 a is coupled to headerportion 2 b on the side surface 1 c side of plate 1. It is noted thatthe circuit in plate 1 is formed by joining a flat plate and agroove-processed plate, for example.

Heat pipe circuit 2 is formed by evacuating internal space 30 formed inplate 1, and then a predetermined amount of working fluid is charged ininternal space 30. The working fluid is heated by heating means 3 aswill be described later.

FIG. 3 is a sectional view of the isothermal heating apparatus takenalong the line shown in FIG. 1. In FIG. 2, the sectional view of theisothermal heating apparatus in a cross section including the whole ofheader portion 2 b and branch portions 2 a of heat pipe circuit 2 fromside surface 1 c to side surface 1 d of plate 1 is shown. In contrast,in FIG. 3, the sectional view of the isothermal heating apparatus in across section including only header portion 2 b of heat pipe circuit 2is shown. FIG. 3 illustrates the state where working fluid 31 is chargedinto header portion 2 b of heat pipe circuit 2, and working fluid 31 isin contact with an evaporating surface 12 constituting the bottom ofheader portion 2 b having a rectangular shape in cross section. Inheader portion 2 b, working fluid 31 is in contact with evaporatingsurface 12 which is a wall surface of header portion 2 b on the rearsurface 1 b side of plate 1.

Header portion 2 b constituting a part of heat pipe circuit 2 andheating means 3 are arranged with plate 1 interposed therebetween. Asshown in FIG. 3, header portion 2 b of heat pipe circuit 2 has a width 1₁. The width by which heating means 3 is in thermal contact with plate 1is a width 1 ₀. Width 1 ₀ by which heating means 3 is in thermal contactwith plate 1 shall be less than or equal to width 1 ₁ of evaporatingsurface 12. By thus defining the dimensions of heat pipe circuit 2 andheating means 3, heat generated by heating means 3 is more easilytransferred to working fluid 31 in header portion 2 b.

If width 1 ₀ by which heating means 3 is in contact with plate 1 islarger than width 1 ₁ of evaporating surface 12 of header portion 2 b,the amount of heat transferred by heat conduction from heating means 3to front surface 1 a through rear surface 1 b of plate 1 may increase,causing the temperature to be nonuniform on the side surface 1 c sideand side surface 1 d side, on front surface 1 a of plate 1. Bytransferring heat generated by heating means 3 to working fluid 31 andisothermally heating the whole branch portions 2 a by evaporation andcondensation of working fluid 31 as will be described later, plate 1 canbe heated as a whole more isothermally.

Width 1 ₀ by which heating means 3 is in contact with plate 1 may bemade smaller than width 1 ₁ of evaporating surface 12 by about severalmillimeters, for example. The optimal dimensions vary depending on thematerial of plate 1, the wall thickness of plate 1 (after processing ofheat pipe circuit 2), the thickness of plate 1 (i.e., the spacingbetween front surface 1 a and rear surface 1 b), the temperature areaused, and the like.

FIG. 4 is a sectional view showing details of the structure of heatingmeans 3, enlargedly showing side surface 1 c and its surroundings inFIG. 2. As shown in FIG. 4, heating means 3 includes a heater 6, a heattransfer block 4, and a heater holding plate 10. Heat transfer block 4is formed with a grooved recess 4 a for fixing heater 6. Heater 6 as anexample of heating member that supplies heat to working fluid 31 in heatpipe circuit 2 by generating heat is incorporated in recess 4 a as agrooved portion formed in heat transfer block 4. Heat transfer block 4has the function as a storing portion storing heater 6 in recess 4 a.Heater 6 may be an electric heater, for example.

Heater 6 is fitted within recess 4 a formed in heat transfer block 4,and the inside of recess 4 a is filled with heater 6 and a heat transfermaterial 5. Heater 6 is held in recess 4 a of heat transfer block 4 byheater holding plate 10. Heater holding plate 10 has the function as aholding member holding heater 6 in recess 4 a.

Heat transfer block 4 is brought into close contact with and fixed torear surface 1 b immediately below header portion 2 b in plate 1 withheater 6 sandwiched between heat transfer block 4 and heater holdingplate 10 and with heater 6 and heater holding plate 10 crimped by afixing bolt 9. Heating means 3 includes fixing bolt 9 as a fixing memberfixing heater holding plate 10 and heat transfer block 4 integrally toplate 1.

Heat transfer block 4 is in thermal contact with a part of rear surface1 b which is one surface of plate 1, and the part of plate 1 is heatedby heater 6 held in heat transfer block 4.

As to the operation of the isothermal heating apparatus having theabove-described structure, the heat transport principle in theisothermal heating apparatus will be described with reference to FIGS. 2and 4. In the heat transport principle diagrams of FIGS. 2 and 4, a heatflow 21 in the drawings indicates a heat flow from heating means 3 toplate 1. When heater 6 is turned on to generate heat, the heat istransferred to a contact surface 14 between plate 1 and heat transferblock 4 through heat transfer material 5 and heat transfer block 4. Theheat is further transferred through the inside of plate 1 to evaporatingsurface 12 at the bottom of header portion 2 b in plate 1. When thebottom of header portion 2 b in plate 1 is heated by heat flow 21, thebottom of header portion 2 b will be evaporating surface 12 whereworking fluid 31 evaporates.

On evaporating surface 12 in header portion 2 b, working fluid 31charged into the inside of plate 1 is heated. Since the inside of plate1 is in a vacuum decompression state, working fluid 31, when heated, isvaporized promptly to produce a vapor bubble 32. Vapor bubble 32 movesup through working fluid 31 to become vapor 33 at the liquid surface ofworking fluid 31, and vapor 33 moves in heat pipe circuit 2 formed inplate 1 in the direction from the side surface 1 c side to the sidesurface 1 d side to branch off from header portion 2 b, and flows intoeach of plurality of branch portions 2 a.

Vapor 33 moves through internal space 30 formed in plate 1 to move tothe front surface 1 a side opposite to rear surface 1 b to which heatingmeans 3 is attached. Vapor 33 is condensed in each part in branchportions 2 a of heat pipe circuit 2 while moving through internal space30 from the side surface 1 c side to the side surface 1 d side, anddischarges latent heat of condensation to the part of plate 1 that is inthermal contact with branch portions 2 a. In this manner, vapor 33 iscondensed by radiating heat to plate 1, and is transformed into acondensate fluid 34. Heat is transferred isothermally to plate 1 in thewhole branch portions 2 a while vapor 33 flows toward side surface 1 d,and plate 1 absorbs heat from vapor 33, so that plate 1 is heated at anequal temperature.

Since the pressure of vapor 33 flowing through branch portions 2 a ishigher on the side surface 1 c side of plate 1 and decreases toward theside surface 1 d side, the water level of working fluid 31 in branchportions 2 a is higher on the side surface 1 d d side than on the sidesurface 1 c side, as shown in FIG. 2. The level difference of waterlevel causes working fluid 31 to flow back from the side surface 1 dside to the side surface 1 c side where working fluid 31 originallyexists. In the isothermal heating apparatus of the present embodiment,the above-described heat transport from heater 6 to plate 1 is carriedout repeatedly.

Header portion 2 b functions as a heating portion where working fluid 31is heated and evaporated. Branch portions 2 a function as condensationportions where vapor 33 produced by evaporation of working fluid 31exchanges heat with plate 1 and condenses. Header portion 2 b has thefunction as a vapor distributing header that distributes vapor 33produced in header portion 2 b to plurality of branch portions 2 a.Header portion 2 b has the function as a liquid collection header wherecondensate fluid 34 produced by condensation of vapor 33 in plurality ofbranch portions 2 a is collected. Each of plurality of branch portions 2a is, relative to header tubular header portion 2 b, formed as a lateralbranch tubular shape extending in the direction crossing (typically,orthogonal to) the direction in which header portion 2 b extends.

According to the above-described isothermal heating apparatus, heatingmeans 3 is provided on the evaporating surface 12 side which is the wallsurface of header portion 2 b with which working fluid 31 is in contactwhen heating means 3 heats working fluid 31 in the liquid state. Sinceevaporating surface 12 is positioned immediately above contact surface14 where plate 1 and heat transfer block 4 are in contact, the amount ofheat, of heat from heater 6, that is directly transferred to frontsurface 1 a of plate 1 is small. Most of the heat from heater 6 is spentin heating working fluid 31 on evaporating surface 12. When heat pipecircuit 2 and heating means 3 have dimensions defined in FIG. 3, theamount of heat, of the heat generated by heater 6, that is transferredto working fluid 31 is much larger.

Therefore, working fluid 31 in plate 1 can be evaporated, whilepreventing the heat of heater 6 from being directly transferred to plate1, and vapor 33 produced by evaporation of working fluid 31 can bediffused into every part in plate 1. Since working fluid 31 can beevaporated at header portion 2 b in plate 1 to produce vapor 33 andvapor 33 can be condensed at branch portions 2 a to heat plate 1,thermal uniformity of front surface 1 a of plate 1 can be improved.Therefore, the heat-treatment subject mounted on front surface 1 a ofplate 1 can be heated isothermally.

In addition, in the above-described isothermal heating apparatus, plate1 can be heated as a whole by one heating means 3, and a plurality ofheaters as in the system shown in the conventional technique of FIG. 20are not required. Therefore, the number of components can be reduced,and the manufacturing costs of the isothermal heating apparatus can thusbe reduced. Moreover, since heat generated by heater 6 is promptlytransferred to every part of plate 1 by the evaporation phenomenon ofworking fluid 31, the temperature rise of heater 6 can be suppressed andthe amount of heat transferred to the surroundings can also be reduced.Thus, the required energy can be reduced, and the running costs of theisothermal heating apparatus can be reduced. In addition, sinceevaporating surface 12 is provided in plate 1, it is not necessary toprovide an evaporator separately as in the conventional technique ofFIGS. 21 and 22. Therefore, size reduction and further cost reduction ofthe isothermal heating apparatus can be achieved, and the heat capacityof plate 1 can be reduced, so that an isothermal heating apparatushaving high thermal responsiveness can be obtained.

FIG. 5 is a sectional view showing a first variation of the isothermalheating apparatus of the first embodiment. The isothermal heatingapparatus of the first variation shown in FIG. 5 differs from thestructure shown in FIG. 4 in that a thermally conductive interposedmember 7 interposed between plate 1 and heat transfer block 4 isprovided. As shown in FIG. 5, when thermally conductive interposedmember 7 is placed on contact surface 14 between rear surface 1 b ofplate 1 and heat transfer block 4, thermal contact resistance betweenrear surface 1 b of plate 1 and heat transfer block 4 will be reduced.

Therefore, heat generated by heater 6 can be transferred to workingfluid 31 through plate 1 more efficiently, so that thermalresponsiveness of the isothermal heating apparatus is further improved.In addition, the amount of heat radiation radiated from the surfaces ofheat transfer block 4 and heater holding plate 10 to the surroundings isreduced, so that an isothermal heating apparatus having higher thermalefficiency can be provided.

FIG. 6 is a sectional view showing a second variation of the isothermalheating apparatus of the first embodiment. The isothermal heatingapparatus of the second variation shown in FIG. 6 differs from thestructure shown in FIG. 5 in that heating means 3 includes a thermallyconductive interposed member 8 interposed between heat transfer block 4and heater holding plate 10. Heat generated by heater 6 is alsotransferred to heater holding plate 10 through heat transfer material 5.When interposing thermally conductive interposed member 8 between heattransfer block 4 and heater holding plate 10 as shown in FIG. 6, thermalresistance between heater holding plate 10 and heat transfer block 4will be reduced, so that heat is more likely to be transferred fromheater holding plate 10 to heat transfer block 4 as a heat flow 22indicated by an arrow of broken line.

Therefore, the amount of heat lost by radiation to the surroundings, ofheat transferred to heater holding plate 10, can be reduced and heatflow 22 from heater holding plate 10 to heat transfer block 4 can beincreased, so that the heat generated by heater 6 can be transferred toheat transfer block 4 still more efficiently. As a result, since heattransferred from heat transfer block 4 to working fluid 31 through plate1 to heat working fluid 31 increases, thermal responsiveness of theisothermal heating apparatus can further be improved.

FIG. 7 is a sectional view showing a third variation of the isothermalheating apparatus of the first embodiment. The isothermal heatingapparatus of the third variation shown in FIG. 7 differs from thestructure shown in FIG. 5 in that heating means 3 includes a thermallyinsulative interposed member 8 a interposed between heat transfer block4 and heater holding plate 10. FIG. 6 illustrates the example wherethermally conductive interposed member 8 is interposed between heattransfer block 4 and heater holding plate 10. In contrast, the amount ofheat flow flowing from heater 6 to heater holding plate 10 can bereduced by interposing thermally insulative interposed member 8 abetween heat transfer block 4 and heater holding plate 10 as shown inFIG. 7.

Therefore, the amount of heat radiated from heater holding plate 10 tothe surroundings can be reduced, so that the heat generated by heater 6can be transferred to heat transfer block 4 still more efficiently. As aresult, since heat transferred from heat transfer block 4 to workingfluid 31 through plate 1 to heat working fluid 31 increases, thermalresponsiveness of the isothermal heating apparatus can further beimproved. In this case, heater holding plate 10 may be made of amaterial having low thermal conductivity.

Second Embodiment

FIG. 8 is a sectional view of an isothermal heating apparatus of asecond embodiment. The isothermal heating apparatus of the secondembodiment differs from the first embodiment in that heating means 3does not include heat transfer block 4.

That is, in heating means 3 of the second embodiment, heat transferblock 4 is not used, but a groove-like hollowed portion 10 a for fixingheater 6 is formed in heater holding plate 10. Heater 6 is incorporatedin hollowed portion 10 a as a groove portion formed in heater holdingplate 10. Heater 6 is stored in hollowed portion 10 a formed in heaterholding plate 10, and in its surroundings, heat transfer material 5 isarranged. The inside of hollowed portion 10 a is filled with heater 6and heat transfer material 5.

Heater holding plate 10 is fixed by fixing bolt 9 in direct closecontact with rear surface 1 b immediately below header portion 2 b inplate 1. When heating means 3 is constructed in this manner, the numberof components of the isothermal heating apparatus is reduced by notusing heat transfer block 4, so that cost reduction of the isothermalheating apparatus can be achieved.

Third Embodiment

FIG. 9 is a sectional view of an isothermal heating apparatus of a thirdembodiment. The isothermal heating apparatus of the third embodimentdiffers from the first and second embodiments in that the location whereheater 6 is fixed is changed. More specifically, the first embodimentpresents a structure in which heat transfer block 4 and heater holdingplate 10 included in heating means 3 are both fixed to plate 1 usingfixing bolt 9, and heat transfer block 4 is removable from plate 1. Inthe second embodiment, heater 6 is incorporated in groove-like hollowedportion 10 a for fixing heater 6 to heater holding plate 10. On theother hand, in the third embodiment, heat transfer block 4 and plate 1are thermally integrated by a method such as brazing or welding.

In the first and second embodiments, the part fixing heater 6 (heattransfer block 4 in the first embodiment and heater holding plate 10 inthe second embodiment) is a member different from plate 1, and thermalcontact resistance occurs because contact surface 14 between the partfixing heater 6 and plate 1 is not in full close contact. Even whenthermally conductive interposed member 7 is arranged between heattransfer block 4 and plate 1, it is difficult to fully eliminate thermalresistance between heat transfer block 4 and plate 1 though thermalcontact resistance is reduced. In contrast, in the third embodiment,thermal resistance between heat transfer block 4 and rear surface 1 b ofplate 1 can be minimized by thermally integrating heat transfer block 4and plate 1 as shown in FIG. 9.

Therefore, when heat generated by heater 6 and transferred to heattransfer block 4 is further transferred to the plate 1 side throughcontact surface 14 between heat transfer block 4 and plate 1, part ofheat energy can be prevented from being lost. As a result, the amount ofheat transferred from heat transfer block 4 to working fluid 31 throughplate 1 to heat working fluid 31 increases, so that thermalresponsiveness of the isothermal heating apparatus can further beimproved.

FIG. 10 is a sectional view of a variation of the isothermal heatingapparatus of the third embodiment. Comparing FIGS. 9 and 10, hollowedportion 10 a storing heater 6 is formed at a position of heater holdingplate 10 opposed to recess 4 a in the variation shown in FIG. 10. Heater6 is disposed in the inside of recess 4 a formed in heat transfer block4 and in the inside of hollowed portion 10 a formed in heater holdingplate 10. The inside of space formed by recess 4 a and hollowed portion10 a is filled with heater 6 and heat transfer material 5.

The effect of the isothermal heating apparatus of the third embodimentdescribed with reference to FIG. 9 that can reduce thermal resistancebetween heat transfer block 4 and rear surface 1 b of plate 1 does notdepend on the size of heat transfer block 4. That is, as shown in FIG.10, a similar effect can also be obtained by reducing the size of heattransfer block 4 and increasing the size of heater holding plate 10. Inaddition, in the variation shown in FIG. 10, because heat transfer block4 is reduced in size, plate 1 can be cut out and processed from asomewhat larger material integrally with heat transfer block 4.Therefore, the production time of the isothermal heating apparatus canbe shortened, and the manufacturing costs can be reduced.

Fourth Embodiment

FIG. 11 is a sectional view of an isothermal heating apparatus of afourth embodiment. The isothermal heating apparatus of the fourthembodiment has a structure in which heater holding plate 10 of heatingmeans 3 of the third embodiment is metallically joined and integrated toheat transfer block 4.

If heat transfer block 4 and heater holding plate 10 are separatemembers not thermally integrated as in the first to third embodiments,thermal resistance occurs when heat transferred from heater 6 to heaterholding plate 10 is transferred to the heat transfer block 4 side asheat flow 22. In the fourth embodiment, heater holding plate 10 isthermally integrated with heat transfer block 4, and plate 1, heattransfer block 4 and heater holding plate 10 are thermally integrated asa whole.

Therefore, thermal resistance in the path along which the heat generatedby heater 6 is transferred to plate 1 becomes even smaller than in thethird embodiment described above. As a result, the amount of heattransferred from heat transfer block 4 to working fluid 31 through plate1 to heat working fluid 31 increases, so that thermal responsiveness ofthe isothermal heating apparatus can further be improved.

Fifth Embodiment

FIG. 12 is a sectional view of an isothermal heating apparatus of afifth embodiment. The isothermal heating apparatus of the fifthembodiment differs from the fourth embodiment in that a high performanceboiling surface 39 which promotes boiling of working fluid 31 is formedon evaporating surface 12 which is the wall surface of header portion 2b of heat pipe circuit 2 on the side where heating means 3 is provided.High performance boiling surface 39 is to promote heat transfer byboiling heat transfer from heating means 3 to plate 1.

Boiling of working fluid 31 is a phenomenon in which a vapor bubble 32grown from a minute bubble nuclei as an origin in evaporating surface 12moves away from evaporating surface 12. To promote boiling of workingfluid 31, evaporating surface 12 may have a structure whose surface isformed with a large number of minute cavities and minute bubble nucleiare likely to occur. Specifically, high performance boiling surface 39can be obtained by welding metallic particles onto evaporating surface12 of plate 1 or groove-processing evaporating surface 12.

By providing such high performance boiling surface 39, working fluid 31easily boils to become vapor bubbles 32, so that generation of vapor 33is promoted. In the isothermal heating apparatus of the fifthembodiment, as compared to the first to fourth embodiments, the amountof heat transferred to working fluid 31 can be increased, and the amountof heat transferred to front surface 1 a by heat conduction in plate 1can be reduced. Therefore, heat generated by heater 6 can be utilizedfor production of vapor 33 still more efficiently, so that thermalresponsiveness of the isothermal heating apparatus can further beimproved.

Sixth Embodiment

FIG. 13 is a sectional view of an isothermal heating apparatus of asixth embodiment. Although the first embodiment has been described thatbranch portions 2 a of heat pipe circuit 2 formed in plate 1 have anequal groove depth entirely in the direction that branch portions 2 aextend, it is not limited to such a structure. For example, heat pipecircuit 2 may be formed such that the groove depth of branch portions 2a is smaller on the side surface 1 d side than on side surface 1 c sideof plate 1 as shown in FIG. 13.

Then, when horizontally arranging planar plate 1, condensate fluid 34produced by condensation of vapor 33 in branch portions 2 a is morelikely to flow along the inclined bottom of branch portions 2 a from theside surface 1 d side toward the side surface 1 c side. Working fluid 31can thus be easily returned to header portion 2 b where working fluid 31is heated, so that fluid shortage on evaporating surface 12 can beprevented and efficiency of heat pipe circuit 2 can be improved. Inaddition, since the required amount of working fluid 31 can be reduced,thermal responsiveness of the isothermal heating apparatus can furtherbe improved.

Although, in the descriptions of the first to sixth embodiments, thecase where plate 1 is arranged in a horizontal state has beenillustrated, the arrangement of plate 1 is not limited to the horizontalstate. FIGS. 14 and 15 are sectional views each showing another exampleof arrangement of plate 1. As shown in FIG. 14, plate 1 may be arrangedin the vertically standing state, or plate 1 may be arranged in aninclined state as shown in FIG. 15.

Even when plate 1 is arranged in the vertically standing state orinclined state, it is only necessary to locate heating means 3 on thewall surface side of header portion 2 b of heat pipe circuit 2 withwhich working fluid 31 is in contact when heating means 3 heats theworking fluid. Then, the effect of efficiently transferring heat fromheating means 3 to working fluid 31 can also be obtained similarly tothe above. The structure in which heating means 3 is provided on therear surface 1 b side of plate 1 is not a limitation, but in theisothermal heating apparatus arranged as shown in FIGS. 14 and 15, it isalso possible to attach heating means 3 to the side surface 1 c side ofplate 1.

By arbitrarily combining plates 1 in the horizontal, vertical andinclined states, the isothermal heating apparatus of the presentinvention can form a duct, a container or the like surrounding space.When a heat-treatment subject is stored in such a duct or a container,the heat-treatment subject can be heated more isothermally.

Seventh Embodiment

FIG. 16 is a plan view of an isothermal heating apparatus of a seventhembodiment. Although, in the description of the first embodiment, theexample where heat pipe circuit 2 formed in the inside of plate 1includes header portion 2 b and branch portions 2 a processed to extendperpendicularly to header portion 2 b and in parallel to one another hasbeen illustrated, such a structure is not a limitation. For example,heat pipe circuit 2 may further include a coupling portion 2 d couplingbranch portions 2 a extending from header portion 2 b, as shown in FIG.16.

Then, the paths of vapor 33 produced by heating of working fluid 31 inheader portion 2 b increase, so that front surface 1 a of plate 1 can beheated more isothermally. If coupling portion 2 d is formed so as tocouple the tips of branch portions 2 a, then, when forming heat pipecircuit 2 by machining, a tool can be moved relative to plate 1 alongthe loop-like path and perform machining. Therefore, the machining timeof processing plate 1 for forming heat pipe circuit 2 can be shortened,and the manufacturing costs of the isothermal heating apparatus canfurther be reduced.

FIGS. 17 to 19 are plan views of other examples of the isothermalheating apparatus of the seventh embodiment. If heat pipe circuit 2 inthe shapes shown in FIGS. 17 and 18 is formed, the effect that canincrease the paths of vapor 33 to reduce the manufacturing costs of theisothermal heating apparatus can also be obtained similarly to thestructure of FIG. 16. As shown in FIG. 19, if grid-like heat pipecircuit 2 is formed in which a plurality of coupling portions 2 d areprovided and arranged in parallel to one another, the paths of vapor 33can further be increased, and front surface 1 a of plate 1 can be heatedeven more isothermally.

In addition, with a structure in which heat pipe circuit 2 is formedalong the entire circumference of plate 1 as shown in FIGS. 17 to 19,heating by vapor 33 is conducted on all the side surfaces of plate 1,which can reduce temperature drop that would be caused by heatdissipation from edge. Therefore, thermal uniformity of plate 1 can beimproved further as compared to the structure in which heat pipe circuit2 is not provided partly on the side of an end of plate 1 that islocated away from header portion 2 b as shown in FIG. 1 or 16.

While the embodiments of the present invention have been describedabove, the structures of the respective embodiments may be combined asappropriate. It should be understood that the embodiments disclosedherein are illustrative and non-restrictive in every respect. The scopeof the present invention is defined by the claims not by the descriptionabove, and is intended to include any modification within the meaningand scope equivalent to the terms of the claims.

INDUSTRIAL APPLICABILITY

The present invention is particularly advantageously applicable to anisothermal heating apparatus that heats a heat-treatment subject, suchas an organic material for semiconductor manufacture, into anisothermally heated state.

REFERENCE SIGNS LIST

1 plate; 1 a front surface; 1 b rear surface; 1 c, 1 d side surface; 2heat pipe circuit; 2 a branch portion; 2 b header portion; 2 d couplingportion; 3 heating means; 4 heat transfer block; 4 a recess; 5 heattransfer material; 6 heater; 7, 8, 8 a interposed member; 9 fixing bolt;10 heater holding plate; 10 a hollowed portion; 12 evaporating surface;14 contact surface; 21, 22 heat flow; 30 internal space; 31 workingfluid; 32 vapor bubble; 33 vapor; 34 condensate fluid; 39 highperformance boiling surface; 41 first member; 42 second member; 42 aopposed surface.

1. An isothermal heating apparatus comprising: a plate having formedtherein a heat pipe circuit in which a working fluid is charged; andheating means heating said working fluid, wherein said heat pipe circuitincludes a header portion at which the working fluid is heated andevaporated and a plurality of branch portions in which vapor produced byvaporization of said working fluid exchanges heat with said plate andcondensates, said branch portions branching off from said headerportion, and said heating means is provided on a wall surface side ofsaid header portion with which said working fluid is in contact whensaid heating means heats said working fluid.
 2. The isothermal heatingapparatus according to claim 1, wherein said plate is formed to have arectangular shape in plan view, said header portion extends along oneside surface of said plate, and said branch portions are provided toextend toward an other side surface of said plate opposed to said oneside surface.
 3. The isothermal heating apparatus according to claim 2,wherein said plurality of branch portions are arranged in parallel toone another.
 4. The isothermal heating apparatus according to claim 2,wherein said heat pipe circuit further includes a coupling portioncoupling said branch portions.
 5. The isothermal heating apparatusaccording to claim 4, wherein said coupling portion couples tips of saidbranch portions extending from said header portion.
 6. The isothermalheating apparatus according to claim 4, wherein a plurality of saidcoupling portions are provided and are arranged in parallel to oneanother.
 7. The isothermal heating apparatus according to claim 1,wherein said heating means includes a heater, a heat transfer blockformed with a recess and storing said heater in said recess, and aheater holding plate holding said heater in said recess.
 8. Theisothermal heating apparatus according to claim 7, wherein said heatingmeans includes a fixing member fixing said heater holding plate and saidheat transfer block integrally to said plate.
 9. The isothermal heatingapparatus according to claim 7, comprising a thermally conductiveinterposed member interposed between said plate and said heat transferblock.
 10. The isothermal heating apparatus according to claim 7,wherein said heating means includes a thermally conductive interposedmember interposed between said heat transfer block and said heaterholding plate.
 11. The isothermal heating apparatus according to claim7, wherein said heating means includes a thermally insulative interposedmember interposed between said heat transfer block and said heaterholding plate.
 12. The isothermal heating apparatus according to claim7, wherein a hollowed portion storing said heater is formed in saidheater holding plate at a position opposed to said recess.
 13. Theisothermal heating apparatus according to claim 1, wherein a highperformance boiling surface promoting boiling of said working fluid isformed in said wall surface.
 14. The isothermal heating apparatusaccording to claim 1, wherein a width by which said heating means is inthermal contact with said plate is less than or equal to a width of saidwall surface.